Generally, a piezoelectric pump comprises a piezoelectric actuator. Moreover, a driving circuit is needed to drive the piezoelectric actuator, and thus the piezoelectric pump is correspondingly operated.
Conventionally, the driving circuit issues a fixed driving voltage at a fixed frequency to the piezoelectric actuator of the piezoelectric pump when the piezoelectric pump is enabled. Moreover, the driving circuit stops issuing the driving voltage when the piezoelectric pump is disabled. That is, the conventional driving circuit is only able to control the on/off states and the duration of the piezoelectric pump. The conventional piezoelectric pump can be easily operated. However, because of the process variation or other factors, the performance of different piezoelectric pumps may be somewhat different. When the conventional driving circuit is applied to different piezoelectric pumps, the driving results of different piezoelectric pumps are possibly different.
Moreover, the driving circuit issues the fixed driving voltage at the fixed frequency to the piezoelectric actuator of the piezoelectric pump, the pressure of the fluid inhaled or exhaled by the piezoelectric pump cannot be adjusted as required. If the user intends to adjust the pressure of the fluid to a specified value within a specified time interval, an additional fluid control valve is needed. The use of the additional fluid control valve increases the fabricating cost. Moreover, it is difficult to precisely control the fluid control valve, and the use life of the fluid control valve is usually not long. In other words, the fluid control valve is not feasible.
Therefore, there is a need of providing a driving circuit for a piezoelectric pump and a control method thereof in order to eliminate the above drawbacks.